Generally, a monitor mainly includes a video processing circuit and a display device such as CRT (cathode ray tube), LCD (liquid crystal display), PDP (plasma display panel), or the like. CRT has been mainly used so far owing to the advantages in aspect of price and resolution. Yet, LCD expands abruptly in market in aspect of space-saving and various functions in accordance with digital signal processing.
A monitor receives horizontal/vertical synchronization signals (HSYNC/VSYNC) and an R/G/B video signal so as to display a corresponding video, and carries out various information interface such as EDID (extended display identification data) and the like with the video source through DDC (display data channel), i.e. SDA (serial data line)/SCL (serial clock line). Moreover, data communication between the monitor and video source is possible when two-way communication enabling standards such as USB (universal serial bus), IEEE 1394, and the like are applied thereto.
In this case, EDID includes various display characteristic information of the display device of the monitor such as white gamma value, R/G/B chromaticity, R/G/B gamma value, brightness, and current value.
A monitor according to a related art, as shown in FIG. 1, includes a microcomputer 11 such as PC, workstation, or the like performing operation & information processing, grasping a display format of an input video by analyzing frequency information of a horizontal/vertical synchronization signal outputted from a video source 1 generating a video to display a corresponding processing matter on a screen through a video card inside, and outputting a control signal so that an R/G/B video signal transmitted from the video source 1 is signal-processed as a form corresponding to a factory mode closest to the corresponding display format, a video processing unit 12 signal-processing the R/G/B video signal transmitted from the video source 1 to be suitable for the corresponding display format in accordance with the control signal of the microcomputer 11, and a CRT 13 displaying an outputs of the video processing unit 12 on the screen.
Operation of the monitor according to the related art is explained as follows.
First of all, the video source 1 of a computer system transmits the horizontal/vertical synchronization and R/G/B video signals to the monitor 2.
The microcomputer 11 of the monitor 2 grasps the format of the input video in accordance with a frequency of the horizontal/vertical synchronization signal, and controls the video processing unit 12 so that the input video is displayed as the factory mode closest to the video format among factory modes set up previously in the monitor 2.
Subsequently, the video processing unit 12 carries out an image processing such as amplification and the like on the input video to be suitable for the factory mode set up by the microcomputer 11, and then displays the image-processed input video through the CRT 13.
In this case, when the R/G/B signal outputted from the video card of the video source 1 is displayed on the monitor 2, a color that the video card demands to realize is different from a color displayed on the CRT 13 as a display device of the real monitor 2. Besides, the color differs in manufactures of the CRT 13. For instance, an R/G/B ratio outputted from the video card to realize white is different from that for realizing white in the CRT 13.
This is because each CRT 13 has an intrinsic color reproduction characteristic. Such a difference of the color reproduction characteristic is not limited to CRT but includes LCD or PDP.
Unfortunately, the monitor according to the related art fails to implement a demanded color due to the color reproduction characteristic of the applied display device and the color reproduction characteristic difference from the video card. Besides, the color difference occurs between the products of CRT.